I've got a new issue and I'd like to know if there's an elegant solution for this:

I've got users who are in groups. This data is mapped onto Davical. Each group has its own calendar. All regular users (like pupils) are only allowed to *read* their group calendars. This is the easy part which I can control with basic Caldav permissions.

Now we have a separate privilege in our system which can be granted to groups and allows their members (like teachers) to *write* to their group calendars.

Is there a way to map this to Davical without the need to grant each member of this extra groups the read privilege on the group calendars individually? Any "You're allowed to write to all your group collections"-permission I've overseen?